1. Field of the Invention
This invention relates to a silver halide photographic emulsion, and particularly relates to a silver halide photographic emulsion having an elevated spectral sensitivity in green wavelength region. More specifically, the present invention relates to a silver halide photographic emulsion which leads to photographic light-sensitive materials having an elevated spectral sensitivities in green short wavelength region and excellent storage stabilities.
2. Description of the Prior Art
As silver halide photographic emulsions having an elevated spectral sensitivity in a green wavelength region, silver halide photographic emulsions wherein an oxacarbocyanine dye and an imidacarbocyanine dye are used together (for example, Japanese Patent Unexamined Published Application (hereinafter referred to as "J. P. KOKAI") Nos. 59-116646, 59-116647, 59-140443, 59-149346 and the like), those wherein an oxacarbocyanine dye and an oxathiacarbocyanine dye are used together (for example, Japanese Patent Publication for Opposition Purpose (hereinafter referred to as "J. P. KOKOKU") No. 46-11627, J. P. KOKAI No. 60-42750 and the like), those wherein 2 or more oxacarbocyanine dyes are used together (for example, J. P. KOKAI No. 52-23931 and the like), and the like have hitherto been known. However, any of those photographic emulsion has only a low spectral sensitivity in a green short wavelength region, which resulted in a problem on color reproduction.
On the other hand, as sensitizing dyes having a maximal valve of spectral sensitivity between 520 nm and 545 nm, benzimidazolooxazolocarbocyanine dyes (for example, compounds disclosed in J. P. KOKOKU No. 44-14030 and the like) and dimethynemerocyanine dyes (for example, compounds disclosed in U.S. Pat. Nos. 2,493,748, 2,519,001 and 3,480,439 and the like) have hitherto been known. Thus, to solve the above problem, using together a further sensitizing dye having a maximal value of spectral sensitivity between 520 nm and 545 nm may be thought of. However, in emulsions containing a benzimidazolooxazolocarbocyanine or a dimethynemerocyanine, increase of fog owing to a high temperature or a condition of high temperature and high humidity after application of the emulsion, or lowering of sensitivity owing to poorness of stability with time lapse after application of the emulsions is observed. Thus, such a dye does not seem to be suitable for using together.
Under the above circumstances, development of a photographic emulsion which is free from the above drawbacks and has a maximal value of spectral sensitivity in a green short wavelength region, and wherein a new sensitizing dye is used has been desired.